Treat spills and stains as soon as possible. Gently scrape any soil or mop any liquid from the surface of the fabric. Use of soap or detergent with water should be approached with caution since overzealous rinsing to remove soap residue may result in over-wetting, water marking and possible wetting of substructure (this may create other stains or damage products).
For non oil-based stains
Use warm water and non toilet soaps which do not contain optical brighteners (consider Velvet soap, Lux Flakes or Softly). Mix a small amount of soap and warm water solution and apply to the stain, rubbing gently. Blot dry with a clean towel. Apply cool water (preferably rain or distilled water) and blot dry again. Then with a hair dryer working out from the centre of the stain, dry quickly to prevent rings forming. It is generally preferable to clean whole panels of fabric in this way rather than trying to spot clean specific areas.
For oil-based stains
Following the same basic guidelines as above, apply a proprietary brand solvent based cleaner and try to clean generally in panels rather than spot cleaning specific areas. A helpful industry 'secret' is for spot removal of oil based biro marks by the application of a conventional hairspray.